JP2002141663A - Film lamination method - Google Patents

Abstract

(57) [Problem] To provide a film laminating method capable of obtaining a build-up multilayer wiring board having excellent wiring pattern embedding property during lamination and flatness after lamination hardening in a short time. SOLUTION: An adhesive film having a support and a resin composition layer laminated on the surface thereof is overlapped so that the resin composition layer contacts at least a pattern portion on a circuit board, and can be heated and pressed. Using a laminating device having at least one operable heat-resistant rubber press plate, 70-
The adhesive film and the circuit board are pressed at 150 ° C. and 0.05 to 0.9 MPa, and then heated and pressurized, and a laminating apparatus having at least one operable metal press plate is used. A multilayer circuit board is obtained by an adhesive film laminating method including pressing an adhesive film and a circuit board at 0.1 ° C. and 0.1 to 5 MPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laminating a film, and more particularly to a method for manufacturing a build-up type multilayer printed wiring board in which conductive circuit layers and insulating layers are alternately stacked. The present invention relates to a method for laminating an inner circuit pattern.

[0002]

2. Description of the Related Art In a build-up type multilayer printed wiring board, organic insulating layers are alternately stacked on conductor layers of an inner circuit board. In order to stack the organic insulating layer on the inner circuit board, a support and an adhesive film having an organic insulating layer laminated on the surface thereof are overlaid on the inner circuit board,
Next, a method is known in which an inner layer circuit board and an adhesive film are pressed and laminated using a vacuum laminating apparatus having a press plate capable of heating and pressing. Press plate is disclosed in
As disclosed in, for example, Japanese Patent No. 340625, the hardness is important, and a press plate made of heat-resistant rubber is generally used. However, in the case of laminating only with a heat-resistant rubber press plate, the surface of the laminated organic insulating layer has irregularities according to the circuit pattern of the inner circuit board. When the next circuit board is formed on the uneven organic insulating layer and the number of layers is increased, the dimensional accuracy of the entire multilayer circuit board is deteriorated. In particular, when the thickness of the conductor layer of the circuit is larger than the thickness of the organic insulating layer on the adhesive film, the surface irregularities become remarkable. on the other hand,
In order to increase the dimensional accuracy, it has been proposed to use a metal press plate such as stainless steel. When a metal press plate is used, a gap is easily generated between the unevenness of the pattern of the inner circuit board and the adhesive film (poor embedding property).
Therefore, it was necessary to lengthen the pressing time and increase the pressing pressure. When the pressing time is increased and the pressure is increased, the load applied to the organic insulating layer is increased, and the mechanical strength is sometimes reduced.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film laminating method capable of obtaining a build-up multilayer wiring board having excellent wiring pattern embedding during lamination and excellent flatness after lamination hardening in a short time. It is in. The present inventor has conducted intensive studies to achieve the above object, and as a result, when laminating an adhesive film composed of a support and a resin composition layer on an inner circuit board, firstly using a heat resistant rubber press plate. Pressing, and then pressing with a metal press plate, found that the wiring pattern embedding property and the flatness of the insulating (resin composition) layer were significantly improved, and the present invention was completed.

[0004]

Thus, according to the present invention, an adhesive film A having a support and a resin composition layer laminated on its surface is provided on at least a pattern portion on a circuit board by the resin composition. Using a laminating apparatus having at least one operable heat-resistant rubber press plate that can be superposed so that the layers are in contact with each other and that can be heated and pressed, the adhesive film A
And a circuit board, and then pressing using a laminating apparatus having at least one operable metal press plate capable of being heated and pressurized.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the laminating method of the present invention, an adhesive film A having a support and a resin composition layer A laminated on the surface thereof is provided on at least a pattern portion on a circuit board. The adhesive film A and the circuit board are pressed using a laminating apparatus having at least one operable heat-resistant rubber press plate that can be heated and pressed and contacted, and then heated and pressed. Pressing using a laminating device having at least one operable metal press plate. Further, as a preferred embodiment of the present invention, after pressing by a laminating apparatus having a heat-resistant rubber press plate, the support is peeled off from the adhesive film A, and the adhesive film B is overlaid on the resin composition layer A, and the metal film is formed. The method includes pressing by a laminating apparatus having a press plate.

The adhesive film A or B used in the present invention has a support and a resin composition layer A or B laminated on the surface of the support. The support used in the present invention is not particularly limited,
For example, a resin film, a metal foil and the like can be mentioned. As the resin film, a thermoplastic resin film is usually mentioned. Specifically, polypropylene film, polyethylene film, polybutene film, polypentene film, polyvinyl chloride film, polycarbonate film, polyethylene terephthalate film, polyethylene naphthalate film, polyarylate film, nylon film, ethylene-vinyl acetate copolymer film , An ethylene-ethyl acrylate copolymer film, an acrylic resin film, and the like. Among these resin films, polyester films such as a polyethylene terephthalate film and a polyethylene naphthalate film are preferred from the viewpoints of heat resistance, chemical resistance, and peelability after lamination. Examples of the metal foil include a copper foil, an aluminum foil, a nickel foil, a chrome foil, a gold foil, and a silver foil. Among these metal foils, copper foils, particularly electrolytic copper foils and rolled copper foils, are preferred because of their good conductivity and low cost.

Although the thickness of the support is not particularly limited, it is usually 1 μm to 200 μm, preferably 3 μm to 100 μm, more preferably 10 to 50 μm from the viewpoint of workability and the like. The elastic modulus of the support is not particularly limited, but a viscoelasticity measuring device DSM6 manufactured by Seiko Instruments Inc.
The modulus of elasticity measured at 100, usually between 100 and 1,500
MPa, preferably 1,000 to 10,000 MPa,
More preferably, it is 3,000 to 8,000 MPa.
When the elastic modulus of the support is in this range, the peel resistance during handling, the peelability of the support after lamination, the embedding property of the wiring pattern of the curable resin composition layer, and the flatness are highly balanced and suitable. It is. Further, the support used in the present invention,
The charging voltage (absolute value) is 500 V or less, preferably 2
Those having a voltage of 00 V or less, more preferably 100 V or less are preferable.

As the curable resin composition laminated on the support, conventionally known curable resin compositions can be used. The curable resin composition usually contains a resin and a curing agent. Examples of the resin constituting the curable resin composition include an epoxy resin, a phenol resin, an acrylic resin, a polyimide resin, a polyamide resin, a polyisocyanate resin, a polyester resin, a polyphenyl ether resin, and an alicyclic olefin polymer. The curable resin composition suitable for use in the present invention contains a resin having a ring structure as an insulating resin from the viewpoints of low dielectric properties, low water absorption, heat resistance, and the like.

The ring structure in the ring structure-containing resin has a main chain and / or
Alternatively, it may be present in any of the side chains, but from the viewpoint of heat resistance and low dielectric properties, those having a ring structure in the main chain are preferred. Examples of the ring structure include an aromatic ring structure and an alicyclic structure. Examples of the ring structure include a monocyclic ring, a polycyclic ring, a condensed polycyclic ring, a bridged ring, and a polycyclic ring obtained by combining these. The number of carbon atoms constituting the ring structure is not particularly limited, but is usually in the range of 4 to 30, preferably 5 to 20, and more preferably 5 to 15. Examples of the resin having a ring structure include a ring structure-containing epoxy resin, a ring structure-containing acrylic resin, a ring structure-containing polyimide resin, a ring structure-containing polyamide resin, a ring structure polyisocyanate resin, a ring structure-containing polyester resin, and a polyphenylene ether. Resins, benzocyclobutene resins, polynorbornene resins, and the like. Among these, ring structure-containing epoxy resins, polyphenylene ether resins, benzocyclobutene resins, polynorbornene resins, and the like are preferable, and polynorbornene resins are particularly preferable. .

The curing agent constituting the curable resin composition used in the present invention is not particularly limited, and examples thereof include an ionic curing agent, a radical curing agent, and a curing agent having both ionic and radical properties. Is used. An ionic curing agent is preferred from the viewpoints of insulation resistance, heat resistance, chemical resistance, and compatibility with the alicyclic olefin polymer. Further, in order to accelerate the curing reaction, a curing accelerator or a curing aid can be used.

Examples of the composition using a ring structure-containing epoxy resin include those described in JP-A-11-1547, and the composition using a polyphenylene ether resin is described in JP-A-9-290481. Examples of the composition using a benzocyclobutene resin include those described in JP-A-11-16883 and the like. The composition using a polynorbornene-based resin is described in International Publication WO / 98/98. No. 56011 and the like.

The curable resin composition used in the present invention is not particularly limited by the dielectric constant of a cured product obtained by curing the same, but the value of the dielectric constant measured at 1 MHz according to JIS C6481 is usually 4%. Or less, preferably 3.5 or less, more preferably 3 or less. The curable resin composition used in the present invention has a water absorption of a cured product obtained by curing the composition, which is a value measured according to JIS C6481 and is usually 0.5% or less, preferably 0.3% or less. , More preferably 0.1% or less.

The curable resin composition of the present invention is not particularly limited by the melt viscosity characteristics at 120 ° C. before being cured after being laminated on the support, but is preferably RDA-II manufactured by Rheometrics. Of the curable resin composition A on the adhesive film A is usually 1,000 to 100,000 at a value measured using a dynamic viscoelasticity measuring device of
Pa · s, preferably 5,000 to 80,000 Pa · s
s, more preferably 10,000 to 30,000 Pa.
s, and the curable resin composition B on the adhesive film B is usually 10,000 to 200,000 Pa · s, preferably 15,000 to 100,000 Pa · s, more preferably 20,000 to 50 Pa · s. 2,000 Pa · s. When the melt viscosity property at 120 ° C. of the curable resin composition layer is excessively small, the flatness of the resin layer surface is poor,
Further, the resin composition may exude at the time of pressing and cause problems such as contamination of the press plate. Conversely, if it is too large, the wiring pattern embedding property and flatness may be poor.

The thickness of the curable resin composition layer on the adhesive films A and B is usually 10 to 200 μm, preferably 15 to 200 μm.
To 150 μm, more preferably 20 to 100 μm. When the adhesive films A and B are laminated, the thickness of the curable resin composition layer on the adhesive film A is preferably equal to or greater than that on the adhesive film B or greater than that on the adhesive film B. . When the adhesive films A and B are laminated, it is preferable that the thickness of the curable resin composition layer on the adhesive films A and B is smaller than the thickness of the conductor layer of the circuit board. Preferably, it is about 30 μm or less. The area of the support and the curable resin composition layer may be the same area, but since the support is peeled off after being laminated on the inner layer substrate, the support is hardened by the curable resin composition. Those having a slightly larger area than the material layer are preferred.

As a method of laminating the support and the curable resin composition layer, a method in which the curable resin composition formed in the form of a film and the support in the form of a film are superimposed and brought into close contact with each other can be employed. Are preferably laminated by a solution casting method or a melt casting method. In the solution casting method, after applying a solution or dispersion of the curable resin composition to a support, the solvent is removed by drying.

The solvent used for dissolving or dispersing the curable resin composition includes, for example, aromatic hydrocarbon solvents such as toluene, xylene, ethylbenzene and trimethylbenzene; n-pentane, n-hexane and n-hexane. Aliphatic hydrocarbon solvents such as heptane; cyclopentane,
Alicyclic hydrocarbon solvents such as cyclohexane; halogenated hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone; These solvents can be used alone or in combination of two or more. Among these solvents, non-polar solvents such as aromatic hydrocarbon-based solvents and alicyclic hydrocarbon-based solvents and polar solvents such as ketone-based solvents have excellent embedding properties in fine wiring and do not generate bubbles. A mixed solvent obtained by mixing with a solvent is preferred. The mixing ratio of the nonpolar solvent and the polar solvent can be appropriately selected, but is usually 5:95 to 95: 5, preferably 10:90 by weight.
９０90: 10, more preferably 20:80 to 80:20
Range. The amount of the solvent used is appropriately selected depending on the purpose of use, but the solid concentration of the solution or dispersion of the curable resin composition is usually 5 to 70% by weight, preferably 10 to 6% by weight.
The range is 5% by weight, more preferably 20 to 60% by weight.

The coating method includes dip coating, roll coating, curtain coating, die coating, slit coating and the like. The conditions for removing and drying the solvent are appropriately selected depending on the type of the solvent, the drying temperature is usually 20 to 300 ° C., preferably 30 to 200 ° C., and the drying time is usually 30 seconds to 1 hour, preferably 1 second. Min to 30
Minutes. The curable resin composition layer is preferably in a so-called B-stage state. The B stage state can be obtained by appropriately selecting the above drying conditions. In the preferred method for producing an adhesive film of the present invention, an operation of irradiating the support with soft X-rays, an operation of contacting an alcohol or a surfactant, and further laminating a layer of the curable resin composition on the support are performed. Perform the operation. All of these operations are preferably performed in a clean room with a small number of fine particles. The clean room usually has a cleanness of class 10000 or less, preferably class 1000 or less, particularly preferably class 500 or less. The adhesive film comprising the resin composition layer at room temperature solid and the support is stored as it is or by further laminating a protective film on the other surface of the resin composition layer, winding up in a roll shape, and storing. At the time of pressing, after removing the protective film, the resin composition layer of the adhesive film is superimposed on the patterned circuit board.

The circuit board used in the present invention may have a circuit pattern formed of a conductor layer on one or both sides. When both sides are patterned, if two adhesive films are used on both sides of the circuit board, the resin composition layer of the adhesive film can be simultaneously laminated on both sides of the circuit board on the patterned circuit board. Although the thickness of the conductor layer of the circuit board is not particularly limited, it is usually 1 to 400 μm.
m, preferably 10 to 200 μm, more preferably 3 to 200 μm.
0 to 100 μm.

In the laminating method of the present invention, first, the adhesive film A is overlaid so that the resin composition layer is in contact with at least the pattern portion on the circuit board, and the adhesive film A and the circuit board are positioned. . Next, the adhesive film A and the circuit board are pressed by using a laminating apparatus having at least one heat-resistant rubber press plate capable of being heated and pressed, and further heated and pressurized and at least one operable. Is pressed using a laminating apparatus having a metal press plate. The laminating apparatus may have a press plate capable of heating and pressurizing, and the press mechanism in the laminating apparatus may be a method in which one press plate is operated, or a method in which a pair of press plates are operated and both are operated. Good. Further, the press plate may be fixed to the laminating device or may be removable. Examples of the laminating apparatus include commercially available vacuum laminating machines such as a vacuum applicator manufactured by Morton International Incorporated, a vacuum press machine manufactured by Meiki Seisakusho, and a vacuum laminator manufactured by OPTEK.

In the pressing step using a heat-resistant rubber press plate, the positioned adhesive film A and the circuit board are pressed from the support side of the adhesive film A (hereinafter, sometimes referred to as a primary press). Primary press temperature is usually 7
The temperature is 0 to 150 ° C, preferably 80 to 130 ° C, and the primary pressing pressure is usually 0.05 to 0.9 MPa, preferably 0.1 to 0.7 MPa. Primary press time is usually 1
Seconds to about 120 seconds. In order to enhance the adhesion between the adhesive film A and the circuit board, it is preferable to set the press atmosphere to normal pressure or lower. The degree of vacuum is preferably 400 mmHg
vac. ７760 mmHg vac. It is.

In the pressing step using a metal press plate, the adhesive film A and the circuit board that have been subjected to the primary press are pressed again (hereinafter sometimes referred to as a secondary press). The secondary pressing temperature is usually 110 to 170 ° C, preferably 12 to 170 ° C.
0 to 150 ° C, secondary press pressure is usually 0.1 to 5M
Pa, preferably 0.5 to 3 MPa. The secondary pressing time is usually about 1 second to 120 seconds. In order to enhance the adhesion between the adhesive film and the circuit board, it is preferable to set the press atmosphere to normal pressure or lower. The degree of vacuum is preferably 40
0 mmHg vac. ７760 mmHg vac. It is. The metal press plate used in the pressing process using the metal press plate is not limited to the one fixed to the laminating device, but may be used in a laminating device having a heat resistant rubber press plate. Alternatively, a metal plate such as stainless steel may be interposed between the substrate and the circuit board and pressed. As a preferred embodiment of the present invention, in a pressing step using a metal press plate, the support of the primary pressed adhesive film A is peeled off, and the adhesive film B is removed.
Is superimposed on the resin composition layer A, and the adhesive film B is pressed on the resin composition layer A. The secondary pressing temperature when laminating the adhesive film B is usually 70 to 150 ° C, preferably 80 to 130 ° C.

It is preferable that the pressing time in the step using the heat-resistant rubber press plate and the pressing time in the step using the metal press plate are substantially the same. By making the pressing times the same, the waiting time from the process using the heat-resistant rubber press plate to the process using the metal press plate is eliminated, and the productivity can be increased.

The method of vacuum laminating the resin composition layer of the present invention on a patterned circuit board is not limited to the case where the resin composition layer is used for an interlayer resin composition layer for build-up. The present invention is also applicable to general resin composition layers, for example, dry films such as solder resists. After lamination, a curing reaction is usually performed in an oven. The curing conditions are appropriately selected according to the type of the curing agent, and the curing temperature is usually 30 to 400 ° C, preferably 70 to 300 ° C,
More preferably 100 to 200 ° C., and the curing time is
It is usually 0.1 to 5 hours, preferably 0.5 to 3 hours. When the support-attached film or sheet is laminated on an inner layer substrate, the film or sheet made of a curable resin composition may be heated and cured while the support is attached, but usually the support After the body is peeled off, the film or sheet made of the curable resin composition is heated and cured.

[0024]

The present invention will be specifically described below with reference to examples and comparative examples. In the examples, “parts” means “parts by weight” unless otherwise specified. (1) Unless otherwise specified, the molecular weight was measured as a polystyrene equivalent value by gel permeation chromatography (GPC) using toluene as a solvent. (2) Hydrogenation rate (ratio of moles of hydrogenated hydrogen to moles of unsaturated bond in polymer before hydrogenation) and carboxyl group content (carboxyl group to total number of monomer units in polymer) Is the ratio of ¹ H-N
It was determined from the measurement results by MR. (3) The glass transition temperature (Tg) is determined by the differential scanning calorimetry (D
SC method). (4) Melt viscosity (Eta *) is measured by Rheometrics R
It measured using DA-II. The resin composition on the support was peeled from the support, and the measurement frequency was 0.5 Hz and the measurement temperature was 6
The melt viscosity at 120 ° C. was evaluated by measuring the temperature at 0 ° C. to 180 ° C. at a temperature rising rate of 2 ° C./min.

(5) Tact time is represented as processing time per substrate. Since the primary press and the secondary press can be processed in parallel, the longer time taken for each of the primary press and the secondary press was taken as the tact time. When a plurality of sheets were processed at the same time, the total processing time was divided by the number of processed sheets. (6) Regarding the embedding property during wiring, the wiring board was cut, and the presence or absence of voids was observed with a scanning electron microscope. Evaluation is wiring 100
Regarding the book, ◎ indicates that no voids were formed, ○ indicates that the voids were at 1 to 3 locations, △ indicates that the voids were at 4 to 6 locations, and x indicates that the voids were 7 or more. (7) The generation of bubbles during the lamination was visually observed from the upper surface of the cured product layer of the wiring board, and the presence or absence of bubbles was confirmed. A sample in which no air bubbles were observed in the 100 mm area was evaluated as ○, a sample in 1 to 5 locations was rated as Δ, and a sample in 6 to 10 locations was rated as ×. (8) The flatness of the cured product was measured by cutting a wiring board having a wiring thickness of 18 μm and measuring the thickness of the cured product layer with a scanning microscope. The evaluation is as follows: the difference between the thinnest part and the thickest part is 0 micron or more and less than 2 microns. ◎: 2 microns or more and less than 3 microns. ○: 3 microns or more but less than 8 microns. Δ: 8 microns or more. Is indicated by x. (9) The thickness of the cured resin layer on the conductor layer was measured by cutting a circuit board and observing it with a scanning microscope.

Example 1 50 mol% of tetracyclododecene (TCD) and 50 mol% of 8-methyltetracyclododecene (MTD) were subjected to ring-opening polymerization, and then hydrogenated to a hydrogenation rate of 99%. TCD with number average molecular weight (Mn) = 31,200, weight average molecular weight (Mw) = 55,800, and Tg = 158 ° C.
/ MTD ring-opening copolymer hydride was obtained. 28 parts of this hydrogenated ring-opening copolymer, 12 parts of maleic anhydride and 3 parts of dicumyl peroxide were dissolved in 130 parts of t-butylbenzene and reacted at 140 ° C. for 6 hours. The obtained reaction product solution was poured into 300 parts of methanol to coagulate the reaction product. The coagulated product was vacuum dried at 100 ° C. for 20 hours to obtain a hydrogenated maleic acid-modified ring-opened polymer. The molecular weight of the hydrogenated maleic acid-modified ring-opening polymer is Mn = 33.2.
00, Mw = 68,300, Tg was 170 ° C., and the maleic acid group content was 25 mol%.

Maleic acid-modified ring-opening polymer hydride 100
Parts, diallyl monoglycidyl isocyanate 53.2
Parts, dicumyl peroxide 5.42 parts and polyphosphoric acid melamine salt (trade name: MPP-C: Sanwa Chemical Co., Ltd.) 30 parts xylene 170 parts and cyclopentanone 1
It was dissolved in 10 parts of a mixed solvent to obtain a varnish of the curable resin composition. This varnish was filtered through a precision filter made of Teflon (registered trademark) having a pore size of 10 μm, and then, using a die coater, a 300 mm square 75 μm thick polyethylene naphthalate film (trade name: Teonex: manufactured by Teijin Limited) was used. It was coated and then dried in a nitrogen oven at 100 ° C. for 600 seconds to obtain a dry film with a support having a resin thickness of 40 μm. The melt viscosity of the resin composition on the support was 25,000 Pa · s.

A conductor wiring layer having a wiring width and an inter-wiring distance of 165 microns and a conductor layer thickness of 18 microns;
0.8mm thick with 2mm plated through hole
The inner substrate having a thickness of 1 mm was washed with a 1 mol / l aqueous solution of sodium hydroxide to remove impurities on the substrate, washed with water, and dried. Next, the above-described dry film with a support was superposed on both surfaces of the inner layer substrate after the above-mentioned cleaning treatment, with the support being on the outside and the curable resin composition layer being on the inside.
Using a vacuum laminator equipped with heat-resistant rubber press plates on the top and bottom, this was vacuumed at 758 mmHg vac. At a temperature of 110 ° C. and a pressure of 0.5 MPa for 60 seconds (primary press). Next, using a vacuum laminating apparatus having upper and lower heat resistant rubber press plates covered with a stainless steel press plate, a degree of vacuum of 758 mmHg vac. At temperature 1
Thermocompression bonding was performed at 40 ° C. and a pressure of 1.0 MPa for 60 seconds (secondary press). Then, only the support was peeled off and left in a nitrogen oven at 150 ° C. for 120 minutes to form an electric insulating layer on the inner substrate. Table 1 shows the evaluation results of the circuit board.

Example 2 A circuit board was obtained in the same manner as in Example 1 except that the pressing pressure and the heating temperature in the primary pressing step were changed to 0.1 MPa and 100 ° C., respectively. Table 1 shows the evaluation results. Example 3 As a varnish of a curable resin composition, 100 parts of a hydrogenated maleic acid-modified ring-opening polymer, 50 parts of a brominated bisphenol A type epoxy resin (trade name: Araldite AER8049: manufactured by Asahi Ciba Co., Ltd.), 1-benzyl 0.1 part of 2-phenylimidazole, 10 parts of antimony pentoxide, and 5 parts of silicone resin (Tospearl 120: manufactured by Toshiba Silicone Co., Ltd.) are 135 parts of xylene and 90 parts of cyclopentanone.
A circuit board was obtained in the same manner as in Example 1 except for using a varnish of a curable resin composition obtained by dissolving in a part of a mixed solvent.
The melt viscosity of the resin composition on the support is 38,000 Pa ·
s. Table 1 shows the evaluation results.

Example 4 A circuit board was obtained in the same manner as in Example 3 except that the amount of the brominated bisphenol A type epoxy resin was changed to 100 parts. The melt viscosity of the resin composition on this support is 11,000 Pa · s
Met. Table 1 shows the evaluation results. Example 5 In a secondary press, ten substrates and nine stainless steel plates were alternately stacked, and ten substrates were formed using a vacuum laminating apparatus.
Vacuum degree 750 mmHg vac. A circuit board was obtained in the same manner as in Example 1, except that the substrate was heated and pressed at a temperature of 130 ° C. and a press pressure of 2 MPa for 20 minutes. Table 1 shows the evaluation results.

Comparative Example 1 A circuit board was obtained in the same manner as in Example 1 except that the secondary press using the vacuum laminating apparatus was not performed. Table 1 shows the evaluation results. Comparative Example 2 A secondary press using a stainless steel plate was performed without performing the primary press, and the degree of vacuum was 758 mmHgvac. A circuit board was obtained in the same manner as in Example 1 except that the test was performed at a temperature of 120 ° C. and a press pressure of 1.0 MPa for 60 seconds. Table 1 shows the evaluation results. Comparative Example 3 A circuit board was obtained in the same manner as in Comparative Example 2 except that a secondary press was performed with a polypropylene sheet having a thickness of 0.1 mm being sandwiched in place of the stainless steel plate. Table 1 shows the evaluation results. Comparative Example 4 A circuit board was obtained in the same manner as in Comparative Example 3, except that the heating and pressing time was changed to 600 seconds. Table 1 shows the evaluation results. It can be seen that the pressurization time must be increased in order to improve the embedding property. It can also be seen that the smoothness hardly changes (is not improved) even when the pressing time is increased.

Example 6 A circuit board was obtained in the same manner as in Example 1 except that the varnish used in Example 1 was changed to a varnish obtained by the following method. 8
-Ethyl-tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -Dodeca-3-ene is subjected to ring-opening polymerization, followed by a hydrogenation reaction, and number average molecular weight (Mn) = 31,20.
A hydrogenated polymer having a weight average molecular weight (Mw) of 55,800 and a Tg of about 140 ° C. was obtained. The hydrogenation rate of the obtained polymer was 99% or more. Obtained hydrogenated polymer 2
8 parts, 10 parts of maleic anhydride and 3 parts of dicumyl peroxide are dissolved in 130 parts of t-butylbenzene.
For 6 hours. The obtained reaction product solution was added to 30
The reaction product was solidified by pouring into 0 parts of methanol to obtain a maleic acid-modified hydrogenated polymer. The modified hydrogenated polymer was vacuum dried at 100 ° C. for 20 hours. The molecular weight of this modified hydrogenated polymer is Mn = 33,200, Mw = 68,30.
At 0, the Tg was 170 ° C. Maleic acid group content is 2
It was 5 mol%. 100 parts of hydrogenated maleic acid-modified ring-opening polymer, 50 parts of 1,3-diallyl-5-glycidyl isocyanurate, 5 parts of dicumyl peroxide and melamine polyphosphate (trade name: MPP-C: Sanwa Corporation) (Chemical) 30 parts was dissolved in a mixed solvent of xylene 170 parts and cyclopentanone 110 parts to obtain a varnish of a curable resin composition. The varnish was filtered with a Teflon precision filter having a pore diameter of 10 microns. This varnish was used. The melt viscosity of the resin composition on the support is 24,000P
a · s. Table 1 shows the evaluation results.

[0033]

[Table 1]

From Table 1, it can be seen that the circuit board obtained by performing the press step (primary press) using a heat-resistant rubber press plate and the subsequent press step (secondary press) using a stainless steel press plate has a good embedding property. It can be seen that the surface smoothness is excellent. Particularly, a resin composition having a melt viscosity of 10,000 to 30,000 Pa · s has an excellent balance between smoothness and embedding property (Example 1 or 6). On the other hand, it can be seen that the circuit board obtained by performing only the pressing step using a heat-resistant rubber press plate has irregularities in accordance with the pattern of the inner layer substrate and has poor surface smoothness (Comparative Example 1). In addition, it can be seen that a circuit board obtained by performing only the pressing step using a metal press plate is inferior in embedding property and causes problems such as generation of bubbles (Comparative Example 2). Further, when a sheet such as a polypropylene film is interposed, it can be seen that long-time heat-compression bonding is necessary to bring the embedding property and the smoothness to desired standards (Comparative Examples 3 and 4).

Example 7 The varnish used in Example 6 was treated with a die coater for 300 minutes.
A 75 μm-thick polyethylene naphthalate film (trade name: Teonex: manufactured by Teijin Limited) having a thickness of 75 mm square, dried in a nitrogen oven at 100 ° C. for 600 seconds, and dried with a 25 μm-thick resin-supported dry film A and B was obtained. The melt viscosities of the resin compositions A and B on the support were 25,000 Pa · s. Conductive layer removal rate 60
% Pattern and wiring width and distance between wirings are 165 μm
And a conductor wiring layer having a conductor layer thickness of 50 μm and a diameter of 0.3
0.8m thick with plated through holes of mm
m of the inner layer substrate was washed with a 1 mol / l aqueous solution of sodium hydroxide to remove impurities on the substrate, washed with water, and dried. Next, the aforementioned dry film A with a support was
The substrate was superposed on both sides of the inner layer substrate after the above-mentioned cleaning treatment, with the support on the outside and the curable resin composition layer on the inside. Using a vacuum laminator equipped with heat-resistant rubber press plates on the top and bottom, this was vacuumed at 758 mmHg vac. At a temperature of 110 ° C. and a pressure of 0.5 MPa for 60 seconds (primary press). The support was peeled off from the dry film A, then the dry film B with the support was overlaid, and the vacuum degree was 758 mmHg v using a vacuum laminating apparatus equipped with a heat-resistant rubber press plate covered with a metal press plate.
ac. At a temperature of 130 ° C. and a pressure of 0.5 MPa for 60 seconds (secondary press). Then, the support was peeled off from the dry film B, and left in a nitrogen oven at 150 ° C. for 120 minutes to form an electric insulating layer on the inner substrate. Table 2 shows the evaluation results of this circuit board.

Example 8 A circuit board was obtained in the same manner as in Example 7 except that the resin thickness of the dry film A with the support was changed to 35 μm and the resin thickness of the dry film B with the support was changed to 15 μm. Table 2 shows the evaluation results. Example 9 A circuit board was obtained in the same manner as in Example 7, except that the varnish of the curable resin composition was changed to the varnish used in Example 3.
The melt viscosities of the resin compositions A and B on the support were 38,000
0 Pa · s and the resin thickness was 25 μm. Table 2 shows the evaluation results. Example 10 A dry film A with a support was obtained by the varnish used in Example 6, and the melt viscosity of the resin composition A was 25,000 P
a · s, the resin thickness was changed to 45 μm, and a dry film B with a support was obtained by the varnish used in Example 3, and the melt viscosity of the resin composition B was 38,000 Pa · s.
A circuit board was obtained in the same manner as in Example 7, except that the thickness of the resin was changed to 15 μm. Table 2 shows the evaluation results.

COMPARATIVE EXAMPLE 5 A circuit was prepared in the same manner as in Example 7 except that a primary press was performed using a dry film with a resin of a resin composition having a thickness of 50 μm and a secondary press was not performed using a vacuum laminating apparatus. A substrate was obtained. Table 2 shows the evaluation results. Comparative Example 6 A dry film with a support having a resin thickness of 50 μm of the resin composition was used, and the degree of vacuum was 758 m without primary pressing.
mHg vac. , Press temperature 120 ° C, press pressure 1.
A circuit board was obtained in the same manner as in Example 7, except that only the secondary press was performed at 0 MPa for 60 seconds. Table 2 shows the evaluation results.

[0038]

[Table 2]

From Table 2, it can be seen that by performing the primary press and the secondary press, the embedding property into a circuit having a wiring pattern with a thick conductor layer is good and the surface smoothness is also excellent. The melt viscosity of the resin composition used for the primary press is 10,000 to 30,000 Pa · s, and the resin composition used for the secondary press is 20,000 to 50,000 Pa · s.
s, and the thickness of the resin layer used for the primary press is the same or larger than that used for the secondary press, and when the same or thicker is used, the balance between smoothness and embedding properties is particularly excellent ( Example 10). On the other hand, it can be seen that the circuit board obtained by performing only the pressing step using the heat-resistant rubber press plate has irregularities in accordance with the pattern of the inner layer substrate and has poor surface smoothness (Comparative Example 5). In addition, it can be seen that a circuit board obtained by performing only the pressing step using a metal press plate is inferior in embedding property and causes problems such as generation of bubbles (Comparative Example 6).

[0040]

According to the laminating method of the present invention, it is possible to obtain a multilayer circuit board which is excellent in embedding property and surface smoothness even if the time for thermocompression bonding is shortened. In particular, the lamination method of the present invention is excellent in embedding property and surface smoothness of a circuit having a wiring pattern with a thick conductor layer. The multilayer circuit board obtained by the present invention is preferably used for a small and multifunctional electronic device.

Claims (4)

[Claims] 1. An adhesive film A having a support and a resin composition layer A laminated on the surface thereof is superposed such that the resin composition layer A is in contact with at least a pattern portion on a circuit board. The adhesive film A and the circuit board are pressed using a laminating apparatus having at least one pressurizable and heat-resistant rubber press plate that is operable, and then at least one operable metal press that is heatable and pressurizable. A film laminating method, which comprises pressing using a laminating apparatus having a plate. 2. An adhesive film A having a support and a resin composition layer A laminated on the surface thereof is superposed such that the resin composition layer A contacts at least a pattern portion on a circuit board. The adhesive film A and the circuit board are pressed using a laminating apparatus having at least one operable heat-resistant rubber press plate that can be pressurized, and then the support is peeled off from the adhesive film A. An adhesive film B having the laminated resin composition layer B is superimposed on the resin composition layer A such that the resin composition layer B is in contact with the resin composition layer A, and at least one operable metal press that can be heated and pressurized. A film laminating method, comprising: pressing an adhesive film B on a resin composition layer A using a laminating apparatus having a plate. 3. A press by a laminating apparatus having a heat-resistant rubber press plate is performed under the conditions of a press temperature of 70 to 150 ° C. and a press pressure of 0.05 to 0.9 MPa. 3. The film laminating method according to claim 1, wherein the method is performed under the conditions of a pressing temperature of 70 to 170 [deg.] C. and a pressing pressure of 0.1 to 5 MPa. 4. The film laminating method according to claim 1, wherein the resin composition layer of the adhesive film A or B is in a B-stage state.